The present invention relates to a light-emitting diode (LED) lighting system having a helical fiber “filament.”
Lightweight, breakage resistant, high-intensity LEDs, have shown great promise to those interested in replacing conventional tungsten filament light sources. Nevertheless, a problem with such LEDs is that the available visible color spectrum is limited by the finite availability of LED colors. Therefore, in commonly assigned U.S. Pat. No. 7,011,421, and in commonly assigned and co-pending U.S. patent application Ser. No. 11/025,019, which are also incorporated in their entirety herein by this reference, illumination devices are described that uses fluorescent and phosphorescent dyes, thus allowing for emission of light in colors that cannot ordinarily be achieved by use of LEDs alone without significant increase in cost or complexity of the illumination device. However, it is further desirable to easily be able to adjust the color of the light emitted by such LED/dye systems.
Additionally, fluorescent dyes will migrate in a non-uniform illumination field. The non-uniform illumination field will cause dyes exposed to a higher intensity to vibrate and become “hot,”, which then causes the dyes to migrate away from the higher intensity location. As the dyes migrate, the resulting color emitted by the LED/dye system will change. Thus, it is further desirable to reduce or eliminate dye migration in LED/dye systems.